Reissner-Nordstrom black hole is an exact solution of the Einstein-Maxwell theory describing the spacetime outside a collapsing matter with electric charge. Despite it is very unlikely for a collapsing matter to maintain a significant amount of electric charge in real world, still the Reissner-Nordstrom solution has been one of the most discussed topics in gravitational researches [1]} especially black hole related [2]}, [3]}, [4]}, [5]}. Moreover, inspired by the Kerr/CFT correspondence, the charged black hole/CFT holography has been investigated [6]}, [7]}, [8]} where some properties of extremal or near extremal Reissner-Nordstrom black holes can be reproduced by using some two dimensional conformal field theory approaches.
